Resistive-type non-volatile memories (NVMs), such as phase change random access memories (PCRAMs), employ memory elements having different stable resistive states. Such memory elements enable data corresponding to the different resistive states to be stored. The memory element switches from one resistive state to another. For PCRAMs, the switching between the states involves switching between an amorphous and a crystalline phase. The switching between two phases is achieved by heating the memory element using a heater.
However, conventional resistive NVMs have drawbacks. For example, conventional resistive NVMs, such as PCRAMs, require large programming currents to switch from one resistive state to the other. To produce the necessary programming currents, a large transistor is needed. This results in a large cell size. Furthermore, the memory elements are disposed in close proximity with various heat sinks, for example metal lines as well as top and bottom electrodes, contributing to undesired heat loss and low heating efficiency. Inefficient heating and heat loss, as well as the proximity effect on the neighboring cells result in a decrease in reliability and performance and an increase in power consumption due to large programming current requirements.
Therefore, there is a need to improve resistive NVMs.